Introduction The neurohypophysial hormone arginine vasopressin (AVP), also known as antidiuretic hormone, was one of the first hormone identified for its vasopressin properties in 1895 by Oliver and Schäfer. They showed that extract of pituitary gland increased blood pressure in anesthetized dogs. AVP is mainly synthesized in the paraventricular and supraoptic nucleus of the hypothalamus. The hormone is transferred to the neural lobe of the posterior pituitary where it is released to the circulation. Target organs perceive the hormonal stimuli by three different receptors: V1a, V1b and V2. The receptor V1a is mainly expressed in the vascular wall and is responsible for vasoconstriction. The receptor V1b is mainly found in the anterior pituitary, mediating the secretion of the adrenal corticotropin hormone, while the V2 receptor is mainly expressed in nephron tubules triggering water reabsorption. Since the discovery of AVP, both the vasopressin and antidiuretic properties have been very well studied and documented.